This invention relates to roll coating processes, and in particular, to roll coating processes employed in conjunction with ultraviolet coating operations.
Roll coating basically involves the application of a coating to a moving metallic substrate which is fed between two rolls. The coating is fed onto one of the two rolls from other rolls which take up the coating material from a bath. See e.g., SCIENCE AND TECHNOLOGY, Vol. 3, "Coating Methods," pp. 765-830.
Most roll coating machines have been used in conjunction with heat curable coatings. Thus, the coating after it is applied to the substrate has a tendency to flow out on the initial application of heat. This flow-out, however, does not occur when low energy processes are employed. For example, ultraviolet curable coatings have been observed to be deficient in flow properties, especially when roll coating applications methods are employed.
Thus, it is an object of this invention to prepare a roll coating apparatus having improved roll coating capabilities.
It is another object of this invention to prepare a roll coater which eliminates ridges and other surface imperfections from coatings resulting therefrom.
It is another object of this invention to prepare a roll coater which may be utilized in conjunction with low energy curable coatings or with ultraviolet coatings.
These and other objectives are obtained by utilizing the process of the instant invention.